Sama Veda consists of a collection of hymns and sacred texts that are
supposed to be sung instead of just being recited. In classical Sama
Veda, the hymns are sung in praise of God and are basically religious
and philosophical in nature. The hymns of Samaveda are derived from the
Rig Veda and thus impart the lessons of the Rig Veda. It may be called
an abridged version of the Rig Veda, in a melodious form. The melodious
notes are called "Samans", hence the name Sama Veda.
The Sama Veda contains around 1900 verses, 95% of which have been
derived from the Rig Veda. The chanting notations are much more
elaborate than Rig Veda and is each syllable is sung in accordance to
the seven swaras or musical notes. The scale is ascending, descending or
a varied combination. Though the Vedas are considered to be the source
of classical music, the concept of Raga, talas, etc. were developed much
later.
The musical annotation of the Sama Veda is what lends it a unique
character. The Sama Veda is a representation of the rapture of devotion
and spirituality. The essence of Sama Veda and Rig Veda has been summed
up perfectly by the great Vedic scholar David Frawley. He says if Rig
Veda is the word, Sama Veda is the song; if Rig Veda is the knowledge,
Sama Veda is the realization; if Rig Veda is the wife, Sama Veda is the
husband.